I'm not sure I've understood the right way to use WinUAE-Kaillera. Correct me if I'm wrong:

Let's say I'd like to play an ADF game with a distant friend. So, his emulator and mine must have exactly the same configuration (same ROM, same ADF, etc.). Then, we connect with each other. We must then insert the ADF. We must do it at the same time, right? So, it's really hard to be synchronized with each other.

WinUAE-Kaillera must be configured such that the intended game or program will start with no user intervention. In other words interact with the GUI as little as possible, it is rather temperamental at the current stage of development.

Insert all ADF and or HDF files beforehand and test the game runs properly on all ends prior initiating the connection.

There is no support for hot-swapping disks in any version yet. Doing so will absolutely positively desync your game.

Want a game that ought last more than 2 minutes then I recommend using the last beta release available in the WIP section on the site.

2.x is a vast improvement over the 1.x versions even though it is incomplete.